U.S. District Court Judge Colleen Kollar-Kotelly today decided to extend judicial oversight of Microsoft until Nov. 12, 2009. Most terms of the company's landmark 2001 settlement with state and federal governments were set to expire in November 2007. That expiration date was extended until Jan. 31 as Kollar-Kotelly considered motions from most of the states to extend oversight by five years, which Microsoft and the U.S. Department of Justice opposed. Her decision today splits the difference.

More to come shortly.

Update, 5:05 p.m.: Brad Smith, Microsoft's general counsel, has issued a statement:

"We will continue to comply fully with the consent decree. We are gratified that the court recognized our extensive efforts to work cooperatively with the large number of government agencies involved. We built Windows Vista in compliance with these rules, and we will continue to adhere to the decree's requirements."

Kollar-Kotelly issued a 78-page opinion (PDF) and, mercifully, a six-page executive summary (also PDF) "to assist the public in understanding the Court's ruling". She notes "that this is a very complex and unprecedented case and that this summary, by necessity, simplifies the issues."

Kollar-Kotelly based her decision to extend the bulk of the consent decree, also called the final judgments, on "the extreme and unforeseen delay in the availability of complete, accurate, and useable technical documentation relating to the Communications Protocols". These are the links that allow Microsoft's desktop software to interact with its server software, which Microsoft must make available to competitors. The parties already agreed to extend this portion of the consent decree until 2009.

That delay, in Kollar-Kotelly ruled, "constitutes changed circumstances, which have prevented the Final Judgments from achieving their principal objectives. ... The Court's extension should not be viewed as a sanction against Microsoft, but rather as a means to allow the respective provisions of the Final Judgments the opportunity to operate together towards maximizing" the potential of the communications protocols provision to foster competition.

Update, Wednesday: Here's a link to today's story on the ruling.